They are very small Sample size and they most likely offer very little value. However, If the both Hitter and Pitcher have been in the league for 4 or 5 years and there have been 20 to 30 Matchups between them then there is enough sample size there to put some faith into it. But remember you could have a .270 Lifetime hitter that could be have a lifetime 1 for 8 againt a given pitcher and in terms of numbers the next time they matchup it would be in favor of the Hitter because he would be below Average and would be due to get a hit.